1. Field of the Invention
This invention relates to a developing toner supply device, and, more particularly, to a developing toner supply device having a developing toner cartridge detachably mounted thereto.
2. Description of Related Art
A developing toner supply device supplies a developing device with developing toner that develops a latent image formed on a photosensitive drum in an electrophotographic recording apparatus. The developing toner is stored in a casing of the developing toner supply device. The amount of developing toner in the casing decreases through a developing toner supplying operation from the developing toner supply device to the developing device.
Thus, a developing toner cartridge has been conventionally used to supplement the developing toner to the developing toner supply device. The developing toner cartridge stores developing toner therein and is detachably installed into the casing of the developing toner supply device. The developing toner is supplemented from the inside of the developing toner cartridge through a casing side opening of the casing of the developing toner supply device to the casing. As described above, when the developing toner is stored in the developing toner cartridge and is supplemented to the developing toner supply device, the developing toner is prevented from being scattered. Thus, the hands of a user, a recording sheet, peripheral equipment and air are not made dirty, and the device is not obstructed. In contrast, when the developing toner is directly supplied to the casing of the developing toner supply device, developing toner can scatter during transfer.
One known cartridge has an opening formed on a cylindrical member to extend in the longitudinal direction and a shutter for opening and closing the opening rotatably secured along the outer peripheral surface of the cylindrical member. The opening is closed by the shutter when the developing toner cartridge is installed into the casing. It is opened by opening the shutter after the installation of the cartridge into the casing, so that the developing toner is allowed to be supplied into the developing toner supply device. The detachment of the developing toner cartridge from the casing is carried out after the opening is closed by the shutter.
In this type of developing toner cartridge, no developing toner attaches to the outer surface of the closed shutter when the developing toner cartridge is detached from the casing when all of the developing toner in the casing has been used. However, when the shutter is closed to detach the developing toner cartridge from the casing when developing toner remains in the casing, the shutter is moved by plowing through the developing toner to close the cartridge side opening. So, the developing toner attaches to the outer surface of the shutter. Therefore, the hands of the user, the recording sheet, etc. get dirty.